Solid Y is investigated to determine its enthalpy of sublimation. The vapor pressures were measured at five temperatures.
Temperature (K)
Vapor pressure (torr)
270
0.15
290
0.80
310
3.5
330
12.0
350
35.0
Assume the solid behaves ideally in the temperature window studied.
(a) Transform the data so that a linear relationship is obtained, then use an appropriate linear fit to determine the enthalpy of sublimation of solid Y in kJ mol⁻¹. Show all steps in your calculation, including any plots, algebraic manipulations, and the use of physical constants.
(b) Based on the magnitude of the enthalpy you obtained, classify solid Y as ionic, covalent network, molecular, or metallic. Provide two distinct pieces of evidence to support your classification.
(c) Predict how the slope of your linear plot would change (steeper, shallower, or unchanged) if solid Y were an ionic lattice instead, and explain the underlying reason in terms of intermolecular or interionic interactions.